Christopher Hitchens was a pain in the neck. When I last debated with him it was in New York. He stumbled late on stage to draw attention to himself, cigarette and drink in hand, uttering oaths like a prohibition hack. The identikit Trot of our early friendship had became a rabid Bushite defending the Iraq war. He demanded to know how I could love Saddam Hussein so much as to oppose a war against him. I thought he was either in the pay of the Kurds, or had undergone an apotheosis into the ranks of the great American intellectual, a fraternity whose members must spin ideology on a dime and flip a dozen epigrams a night on TV.

I respected Hitchens – or at least the American version – for two sterling qualities. He was fearless in his attacks, and he developed into a stylist of columnar baroque. His mastery of the Oxford Dictionary of Quotations was devastating. Why abuse an opponent when you can get Dr Johnson to do it for you? Who cares if you change opinions more often than a shirt, provided the audience gasps? Why bother what you say, as long as you pay your dues at the hallowed shrine of the English language?

Hitchens seemed deliberately to choose enemies who could answer back, such as Henry Kissinger, the Clintons, Mother Teresa and Gore Vidal, while his friends could not, such as Jefferson, Paine and Orwell. In an age when opinion is customarily terse and glib, Hitchens was Georgian and orotund. His odyssey from International Socialism to Vanity Fair, from opposing the Vietnam war to loving the Iraq one, was accompanied by a shameless self-confidence and a fusillade of justificatory references.

The truth is that amid the noisome banality of wall-to-wall news, strong opinion and passionate conviction expressed in grammatical prose can still draw the crowds. The most encouraging thing about the public realm is that Hitchens could be so phenomenally popular.

When last month Intelligence Squared staged a down-the-line interview with Hitchens at the Royal Festival Hall, compered by Stephen Fry, they wondered if anyone would come. When Hitchens proved too ill to do more than text his replies, they feared a flop. The hall was sold out. Not many journalists could do that, even with the help of such friends and admirers as Richard Dawkins, Martin Amis, Salman Rushdie, Sean Penn and others. The caricature tales of drinking, womanising and U-turning were familiar enough, but what clear was something else, a widespread appreciation of a free spirit that owed nothing to anything but its own turbulent thought processes.